Geoffrey succeeded his father, Tadgh, as chief of the O Donoghues of the Glen (Glenflesk) in 1643. His dwelling place was the stately tower house of Killaha sited at the entrance to the Glen of the Flesk and commanding the approaches to the Glen. He was a prolific poet and renowned for the lavish celebrations and banquets he hosted at Killaha. His castle was slighted by General Ludlow in 1652 who mounted his cannon at Knockanes as he was on his way to confront the Irish at Ross Castle and knocked down the walls of Killaha. Later Geoffrey and his successors lived at other sites in the Glen. Although he and his lands were attainted after the Cromwellian wars, they stubbornly resisted and remained in Glenflesk from which they and their relatives, particularly the O Donoghue Duiv branch, were a scourge to the British well into the 18th Century.
Geoffrey is buried in Muckross Friary where he is memorialised, along with two other Kerry Poets.